Digital Commons Network^™

Understanding Oxidative Aging Of Asphalt Binder And It's Effects On Cracking Susceptibility Of Asphalt Mix, Md Shams Arafat

Doctoral Dissertations

Every year around 400 million tons of asphalt mix is being laid in the United States and a significant portion of it is required for pavement rehabilitation. Cracking is one of the most common pavement distresses that is still not fully understood by the researchers. Very few states mandate tests for cracking resistance during the mix design phase; in addition, the test methods vary a lot from state to state. In the presence of oxygen, the asphalt binder over time undergoes chemical changes and becomes stiff which is known as oxidative aging that makes asphalt pavement more susceptible to cracking. …

Lignin Ethanolysis Depolymerization And Product Upgrading With Mesoporous And Palladium Supported Zeolite Catalysts, Nathan Cody Baxter

Doctoral Dissertations

Lignin is a high-volume farm waste and environmental hazard of paper and pulp industries. To promote the utilization of its rich aromatic units into important chemicals and fuels, efforts were intensively made to breakdown lignin structure with a variety of depolymerization processes involving heating, solvent, and catalysts or their combination. Among those processes, ethanolysis in supercritical conditions shows promising performance for its high lignin conversion and little char formation. To improve the yield and selectivity of aromatics, particularly phenols, we examined the important roles of acidity and pore structure of different zeolite catalyst play in this process. Zeolites with close …

The Sisterhood Ceiling: A Qualitative Case Study On Female Leaders' Perceptions Of The Gender Leadership Gap, Morgan Leigh Patrick

Doctoral Dissertations

Women are underrepresented in leadership (Bichsel & McChesney, 2017; Catalyst, 2018; Cook, 1997; Mesch & Rooney, 2008; United States Senate, n.d.a, n.d.b; United States House of Representatives, 2020a; United States House of Representatives, 2020b). Exploring the underrepresentation of women in higher educational leadership could offer insight that could be used to create opportunities to advance women in order to fill the gender gap. Much is known about the proverbial Glass Ceiling (Bichsel & McChesney, 2017; Catalyst, 2018; Cook, 1997; Mesch & Rooney, 2008) and the Glass Escalator (Malin & Wise, 2018; Maume, 1999; Williams, 1992). However, the challenges related to …

0e2fa: Zero Effort Two-Factor Authentication, Ali Abdullah S. Alqahtani

Doctoral Dissertations

Smart devices (mobile devices, laptops, tablets, etc.) can receive signals from different radio frequency devices that are within range. As these devices move between networks (e.g., Wi-Fi hotspots, cellphone towers, etc.), they receive broadcast messages from access points, some of which can be used to collect useful information. This information can be utilized in a variety of ways, such as to establish a connection, to share information, to locate devices, and to identify users, which is central to this dissertation. The principal benefit of a broadcast message is that smart devices can read and process the embedded information without first …

Development Of A Microarray Biosensor For Real-Time And Continuous Measurement Of Neurochemicals, Md Imran Hossain

Doctoral Dissertations

Continuous simultaneous measurement of glutamate (GLU), an excitatory neurochemical, and γ-aminobutyric acid (GABA), an inhibitory neurochemical, constitutes one of the major challenges in neuroscientific research. Maintaining appropriate levels of GLU and GABA is important for normal brain functions. Abnormal levels of GLU and GABA are responsible for various brain dysfunctions, like epilepsy and traumatic brain injury. GLU and GABA being non-electroactive are challenging to detect in real-time. To date, GABA is detected mainly via microdialysis with a high performance liquid chromatography (HPLC) system that employs electrochemical (EC) and spectroscopic methodologies. However, these systems are bulky and unsuitable for real-time continuous …

Stirred Not Shaken: Functional, Biological, Two-Dimensional Materials, Megan Puglia

Doctoral Dissertations

Herein, the development of high-quality, biophilic two-dimensional nanosheets for use in a diverse array of applications is discussed. Significantly, a potentially universal method for producing nanosheets from their layered crystal counterparts was developed using proteins as dispersing agents. The shearing mechanism was systematically studied and optimized leading to a better understanding of how to prepare these nanosheets for applications as advanced biomaterials.

High concentrations of low-defect, graphene nanosheet suspensions in water (bGr) (10 mg mL^-1) were produced using bovine serum albumin as the dispersant in a continual flow reactor, allowing for nearly 100% conversion of graphite to graphene …

Development Of Decision-Support Tools For Improved Utility Response Following Storm Events And Water Treatment Technologies, Tara Walsh

Doctoral Dissertations

Decision-support tools can provide insights to emergency managers when the situation exceeds their past experience. The intensity of extreme storms is increasing, which leads to more widespread damage. This study developed an agent-based model (ABM) to allow emergency managers to model and test the decisions made in storm restoration. The key factor for using an ABM is that managers can assign specific crew behaviors to simulate different strategies to use in restoration. This study covers the development of an ABM and then applies the model to a specific case study of Hurricane Sandy in a climate-enhanced future. The case study …

Microcracks And Metabolism Within Articular Cartilage During Mechanical Load, Stephany Santos

Doctoral Dissertations

Physical pain limits the quality of life for more than 20% of the adult population around the world. Joint injury and acute trauma account for a significant portion of this pain. The most common joint injuries include ankle sprains, ACL tears in the knee, Patellofemoral syndrome (injury resulting from the repetitive movement of the patella against the femur), and Tennis Elbow (Epicondylitis). There is strong evidence that suggest these injuries trigger a cascade of events that lead to post-traumatic osteoarthritis (PTOA). PTOA is a multifactorial disease that affects all aspects of joints, including ligaments, tendons, bones, menisci, and most prominently, …

Domain-Specific Creativity And Vocational Interests: How Do Creativity And Related Factors Relate To Vocational Interests And Different Latent Riasec Profiles?, Xiaochen Liu

Doctoral Dissertations

Creativity has potential as a key element in understanding students’ vocational interests but has yet to be fully studied. Two questions were proposed: (1) Can potential predictors (demographics, academic achievements, domain-general and domain-specific creativity factors, and the interactions between gender and creativity-related factors) significantly predict vocational interests as derived from Holland’s RIASEC Model and (2) do domain-general and domain-specific creativity factors exhibit differential mean levels across distinct latent vocational profiles?

This dissertation drew on a dataset that collected 4,052 valid responses from grade 9 to 12 students who registered American College Testing (ACT) in the United States for the June …

On The Positivity Of The Discrete Green's Function For Unstructured Finite Elements Discretizations In Three Dimensions, Andrew Miller

Doctoral Dissertations

The aim of this thesis is twofold. First, we will establish new estimates for the discrete Green's function and obtain some positivity results. In particular, we establish that the discrete Green's functions with singularity in the interior of the domain cannot be bounded uniformly with respect of the mesh parameter h. Actually, we show that at the singularity the Green's function is of order h^(-1), which is consistent with the behavior of the continuous Green's function. In addition, we also show that the discrete Green's function is positive and decays exponentially away from the singularity. We also establish numerically persistent …

Tensegrity And Recurrent Neural Networks: Towards An Ecological Model Of Postural Coordination, Martin Fultot

Doctoral Dissertations

Tensegrity systems have been proposed as both the medium of haptic perception and the functional architecture of motor coordination in animals. However, a full working model integrating those two aspects with some form of neural implementation is still lacking. A basic two-dimensional cross-tensegrity plant is designed and its mechanics simulated. The plant is coupled to a Recurrent Neural Network (RNN). The model’s task is to maintain postural balance against gravity despite the intrinsically unstable configuration of the plant. The RNN takes only proprioceptive input about the springs’ lengths and rate of length change and outputs minimum lengths for each spring …

Sequential Estimation Methodologies With Observations Gathered In Groups: Theory, Practice And Data Analysis, Zhe Wang

Doctoral Dissertations

Purely sequential procedure has been widely studied in different inference problems. However, in purely sequential procedure, only one observation should be taken at-a-time. In real life, packaged items purchased in bulk often cost less per unit sample than the cost of an individual item. This dissertation discussed this situation when observations are gathered in groups. First, two fundamental problems on purely sequential estimation are revisited: (i) the fixed-width confidence interval (FWCI) estimation problem, and (ii) the minimum risk point estimation (MRPE) problem, in the context of estimating an unknown mean in a normal population having an unknown variance. We begin …

“This Is A Place Of Business:” The Market Schema And Graduate Employee Unionization In The Corporate University, Kathleen Ragon

Doctoral Dissertations

Scholars, educators, and the public have raised the alarm about the corporatization of higher education in the United States. Graduate employee unions (GEUs) have been at the forefront of this critique of corporatization. However, there is little consensus on exactly what corporatization is or how to measure it. Further still, there is debate about the impact of GEUs themselves on corporatization. This dissertation intervenes in these debates by drawing on the concept of “institutional schemas” (Polletta & Gardner 2015) to create a framework for understanding corporatization and the impact of GEUs on higher education. I draw on qualitative data from …

Automatic Depression Screening And Depressive Symptom Prediction Using Smartphone Sensing Data, Shweta Ware

Doctoral Dissertations

Depression is a common, yet serious health problem. It has significant detrimental impacts on both physical and psychological functioning. Current diagnosis techniques rely on physician-administered or patient self-administered interview tools, which are burdensome and suffer from recall bias. Additionally, these techniques incur higher medical costs. There is an urgent need for an accurate, objective and easily accessible depression screening tool for mass usage. In this dissertation, we explore the usage of smartphone sensing data, collected directly on smartphones or meta-data collected from a WiFi infrastructure, for automatic depression screening and depressive symptom prediction.

In the first part of the dissertation, …

Persisting In Unfamiliar Grounds: A Study Of Black Males Living In A Learning Community While Attending A Predominantly White Institution, Ngozi Taffe

Doctoral Dissertations

Abstract

Black males encounter significant microaggressions and race related challenges as students in Predominantly White Institutions. These encounters negatively impact their college learning and social experiences. In the face of these challenges, college retention rate of Black males falls behind those of other racial and gender groups (Toldson, 2012). Notwithstanding, statistics point to the success and persistence of Black male students in such oppressive environments. Using an Anti-deficit lens and Community Cultural Wealthy framework, this qualitative study explores the learning and social experiences of eight Black males living in a same race same gender learning community while attending a PWI. …

Dynamic Resource Management Algorithms For Complex Systems And Novel Approaches To Adaptive Kalman Filtering, Lingyi Zhang

Doctoral Dissertations

This thesis considers three combinatorial optimization problems of substantial practical importance. First, a new approach to efficiently obtain a large number of ranked solutions to a 3-dimensional assignment problem is presented, and is applied to generate fuel assembly loading patterns. Second, we formulate the problem of dynamically scheduling maritime surveillance assets, and solve it using branch-and-cut and approximate dynamic programming (ADP) with rollout, and investigate the tradeoffs between the two. Third, a multi-objective ship routing problem is also investigated, where we propose a solution combining approximate dynamic programming techniques and clustering techniques to contain the computational and storage complexity. Lastly, …

Gasoline Production Fischer-Tropsch Synthesis Using Bi-Functional Structured Catalytic Reactors, Chunxiang Zhu

Doctoral Dissertations

Gasoline accounts for more than half of U.S. transportation energy usage and its consumption continues growing. Crude oil is where gasoline originates from. However, crude oil reserves are limited in most of the countries around the world. U.S. imports thousand barrels of gasoline per day, making it highly dependent on foreign oil import which imposes a threat to U.S. homeland security. To make the U.S. gasoline independent, alternative processes such as Fischer-Tropsch Synthesis process (FTS) can be promising to mitigate high gasoline demand on transportation fuel and increase fuel diversity. However, scalable, selective, and more efficient FTS technologies are required …

High Electric Field Conduction And Polarization In Polymer Dielectrics, Zongze Li

Doctoral Dissertations

Polymer dielectrics with high energy density are essential elements to fulfill the future needs on pulse power, power conditioning, and electrification applications. The energy density is determined by the breakdown strength and dielectric constant of the polymer dielectrics, essentially controlled by conduction and polarization processes. However, the high field conduction and polarization phenomena of polymer dielectrics with a lack of fundamental understanding are extremely complex involving electronic and conformational structure of polymer, multi-factor interactions from electrical, thermal, mechanical and chemical properties. Thus, the basic experimental and theoretical research on conduction and polarization phenomena of polymer dielectrics under high electric field …

Design Of Materials And Processing Methods For High Temperature Composites, Chris Monteleone

Doctoral Dissertations

In this dissertation, various studies are described which seek to improve the properties of high temperature ceramic-matrix and carbon-matrix composites. Processes were developed and optimized to control the compositions, microstructures, and morphologies of ceramic materials. Focus was on the chemical vapor infiltration (CVI) of coatings on continuous fiber substrates. Other processes were involved as well, such as polymer impregnation & pyrolysis (PIP) and silicon melt infiltration (SMI). Both carbon and SiC fibers were used as substrates. Materials deposited using CVI include carbon, SiC, TiC, BN, and B4C. Characterization methods include scanning electron microscopy, mechanical testing, X-ray diffraction, and others.

A …

Topology Optimization Of Architected Latticeswith Geometric Primitives, Hesaneh Kazemi

Doctoral Dissertations

This thesis advances novel computational techniques to design multi-material, multi-scale and programmable truss lattices. The architecture of lattice materials can be engineered to exhibit desired behavior. I focus on truss lattices made of cylindrical struts, which lead to open-cell designs that are more amenable to additive manufacturing. In this work, I use topology optimization to determine the optimal design of the periodic unit cell to attain extremized mechanical properties. Finite element analysis of the unit cell and numerical homogenization are employed to determine the effective properties of the lattice. To efficiently perform the analysis of the unit cell for any …

Clinician Approaches To Noise-Exposed, “Normal” Hearing Ears: Investigating The Need & Reliability Of A Candidate Measure Of Human Vulnerability To Noise Damage., Sarah Powell

Doctoral Dissertations

It has been well-established that there is large variability between individuals’ vulnerability to noise-induced hearing loss (NIHL), but recent work has galvanized the auditory research and clinical communities to re-evaluate the physiologic and perceptual consequences of subclinical noise-induced damage in individuals that would traditionally be considered “normal hearing.” The auditory efferent system is one potential source of variation between individuals, and research in animal models indicates that strength of the medial olivocochlear reflex (MOCR) is predictive of vulnerability to noise damage because it suppresses cochlear gain. Therefore, it has been proposed that MOCR strength may be useful as a clinical …

Small Molecules To Control Porcine Reproductive And Respiratory Syndrome Virus Infection, Chang Huang

Doctoral Dissertations

Porcine reproductive and respiratory syndrome (PRRS) is an economically significant panzootic affecting the swine industry worldwide. CD163 is the indispensable receptor for PRRS virus (PRRSV) infection and porcine alveolar macrophages (PAMs) are the principle target for productive PRRSV infection in pigs. We validated that the interleukin 10 (IL-10) stimulated Janus kinase (JAK)-signal transducer and activator of transcription 3 (STAT3) signaling upregulates CD163 expression in pig cells. We identified a natural compound cryptotanshinone (Cpt) that inhibits IL-10-stimulated and basal level of CD163 expression in PAMs, and thus suppresses infection of PAMs by type I and type II PRRSV in vitro. …

Stem Identity Authoring: Intergenerational Collaborative Learning In Informal Stem Programs, Laura Rodriguez

Doctoral Dissertations

The problem this research addresses is the lack of opportunities for many people to develop positive identification with STEM fields (i.e., science, technology, engineering and math). This multiple case study will investigate STEM identity authoring in three intergenerational collaborative learning partnerships in an informal STEM program. Adults and high school teens were paired in two-day workshops to learn conservation science and geospatial technologies with the goal of designing and implementing community conservation projects and further developing their identification with STEM. This research examined how the design and implementation of intergenerational projects provided opportunities for: (1) adults and teens to demonstrate …

Development Of A Facebook Group Intervention To Increase Health-Promoting Self-Care Among Primary Caregivers Of Children With Developmental Disabilities, Emily Auerbach Iovino

Doctoral Dissertations

Primary caregivers of children with developmental disabilities (DD) are critical for supporting the development of the children for whom they provide care. In order to most effectively provide care, caregivers of children with DD need to be physically and psychologically healthy. However, caregivers of children with DD can experience challenges in these areas as a result of stress. Health-promoting self-care and social support can mediate the stress process to influence health outcomes. Given that a lack of social support is a barrier to engaging in health-promoting self-care, social support is needed for caregivers to engage in health-promoting self-care and together …

Bias Estimation And Coordinate Conversion In 3-D Sensor Measurements, Michael Kowalski

Doctoral Dissertations

In the field of target tracking there are many challenges associated with error in sensor measurements. Sensors can be subject to sources of consistent error such as temperature warping of the physical equipment, environmental effects in the surrounding atmosphere, and internal clock errors. These errors are known as sensor measurement biases. Biases can corrupt many different types of sensor measurements with many different error models. To overcome such error it is necessary to estimate the biases affecting the system. Two primary methods of bias estimation are examined in this work. The first is simultaneous target state and sensor bias estimation, …

High-Fidelity Modeling Of Buoyancy-Driven Diffusion Flames Towards Fire Suppression, Bifen Wu

Doctoral Dissertations

Buoyancy-driven diffusion flames have been widely studied as a canonical fire configuration due to practical and scientific interests. Numerical investigations are conducted in this dissertation to improve understandings of interactions and couplings among turbulence, chemistry, soot, and multiphase radiation in buoyancy-driven diffusion flames. A high-fidelity modeling framework based on OpenFOAM-5.x, including detailed models for chemistry, radiation, and soot, is developed to improve the numerical accuracy and the computational efficiency with scale-resolved simulations. A Monte Carlo ray tracing (MCRT) based radiation solver coupled with line-by-line databases is developed to describe gas and soot radiation. Detailed and efficient radiation models for water …

Physical Unclonable Functions For Authenticating And Preventing Reverse Engineering Of Integrated Circuits And Electronics Hardware, Md Shahed Enamul Quadir

Doctoral Dissertations

Electronics hardware is subject to a number of potential threats such as reverse engineering and counterfeiting. As a result, hardware authentication mechanisms and anti-reverse engineering techniques such as obfuscation and tamper-resistance are essential. In this thesis, we will present methods to approach these problems, and the primary research contributions of this thesis are a Low pass filter PUF for the authentication of PCBs and ICs; Key generation for hardware obfuscation using strong PUFs; and Session key generation using strong PUF modeling.

Physical Unclonable Functions (PUFs) are probabilistic circuit primitives that extract randomness from the physical characteristics of a device. In …

A Bilateral Perspective Of Acquisition Premiums And Post-Acquisition Performance, Sergio Grove

Doctoral Dissertations

In M&As, to acquire the other companies, managers usually pay a premium. In theory, the premium is explained by the market's acknowledgment of a potential increase in value for both firms standing together and coordinating their resources. The problem is that literature usually explains acquisition premium and post-acquisition performance from a one-sided price perspective. To some extent, this one-sided perspective often captures the acquirer's willingness to pay, but it underestimates the two-sided nature of any transaction; the target's perspective is usually omitted. One side sells when they perceive that the value of their asset is lower than the price paid …

From Patient To Pathways: An Sh2-Based Workflow For Studying Signaling In Chronic Lymphocytic Leukemia Using Biochemical And Computational Methods, Adam Lafontaine

Doctoral Dissertations

Archival abstract submitted

Improving Combination Cancer Immunotherapy With A Novel, Dual-Specific Immunotherapeutic Platform That Links T Cell Costimulatory Pathways, Joseph Ryan

Doctoral Dissertations

Checkpoint-inhibiting antibodies targeting CTLA-4 and PD-1, along with costimulatory agonists, exhibit impressive anti-cancer efficacy and durable tumor regression. Despite this success, however, many patients fail to respond because of multiple immunosuppressive mechanisms used by cancer cells. Combination therapies designed to overcome this show promise, but strategies relying on multiple agents face logistical and regulatory challenges, as well as increased toxicity. This body of work begins with an in-depth review of antibody-based immunomodulatory cancer therapy, with an emphasis on efficacy, toxicity, and their interconnectedness. Following this background, an innovative approach to overcoming fundamental flaws in the current immunotherapy paradigm is presented. …